tlfc CHEMICAL PROPERTIES OF MINERALS. 



TASTE. 



Taste belongs only to the soluble minerals ; the kinds are— 



1. Astringent: the taste of vitriol. 



2. Sweetish-astringent: the taste of alum. 



3. Saline : taste of common salt. 



4. Alkaline : taste^of soda. 



5. Cooling : taste ofNaltpeter. 



6. Bitter: taste of epsofia salts. 



7. Sour: taste of sulphuric §cid. 



ODOR. 



Excepting a few gases and soluble minerals, minerals in 

 the dry, unchanged state, do not give off odor. By friction, 

 moistening with the breath, the action of acids and the blow- 

 pipe, odors are sometimes obtained, which are thus designated : 



1. Alliaceous : the odor of garlic. It is the odor of burn- 

 ing arsenic, and is obtained by friction and more distinctly 

 by means of the blowpipe from several arsenical ores. 



2. Horse-radish odor : the odor of decaying horse-radish. 

 / It is the odor of burning selenium, .ana is strongfy perceived 

 I when ores of this metal are heated before the blowpipe. 



3. Sulphureous : odor of burning sulphur. Friction will 

 elicit this odor from pyrites, /and heat from many sulphurets. 



4. Fetid : the odor of rotten eggs or sulphuretted hydrogen. 

 It is elicited by frictiori from some varieties of quartz and 

 limestone. 



5. Argillaceous: the odor of moistened clay. It is given 

 off by serpentine and some allied minerals when breathed 

 upon. Others, as pyrargillite, afford it when heated. 



CHAPTER IV.— CHEMICAL PROPERTIES OF 



U 



MINERALS. 







ACTION OF ACIDS. 



Acids are used in distinguishing certain minerals that are 

 iecomposed by them. The acids employed are either the 

 pulphuric, muriatic, or nitric. Carbonate of lime, (calca- 



What taste is astringent ? sweetish astringent ? saline ? What wiK 

 develop odor in some minerals ? What is understood by an alliaceous 

 odor? What mineral when heated produces this odor? What is the 

 odor of fumes of selenium ? How is a sulphureous odor obtained from 

 certain minerals? What gas has a fetid odor ? What is an argilla- 

 ceous odor ? 



